1. Field of the Invention
The present invention relates to an improvement of the latch device for the cartridge compartment door of a camera used with a disk type cartridge assembly.
2. Description of the Prior Art
The disk type film cartridge assemblies which are presently on market have an exposure window as shown in a U.S. Pat. No. 4,268,145 and also have a cover member inside of the cartridge which cover member is rotatable for closing said exposure window to prevent the film from being exposed to the light through said exposure window when the cartridge assembly is not loaded in the camera. The cover member is normally locked at the position to cover the exposure window. But, when the cartridge assembly is received in the camera, the lock is released and the cover member is opened by the rotation in the clockwise direction as viewed from the side of cartridge assembly on which the exposure window is provided.
On the other hand, the known cameras used with such a disk type film cartridge assembly are designed to move the cover member to the closing or opening position and to release or lock the latch for the cartridge compartment door at the closing position by the linked motion caused by operation of the same member. And in those cameras, before the lock of the cartridge compartment door at the closing position is released, a driving member which drives the cover member is actuated to move the cover member in the cartridge to the exposure window closing position and the exposure window will always be closed when the cartridge assembly is taken out from the camera. In the conventional cameras, the taking lens is disposed to the right of the camera housing as viewed from the front of the camera housing, and the locking member provided for moving the cover member to the open or closed position and for locking and releasing the cartridge compartment door at its closing position is pivotably mounted at an upper part of the camera housing and by a pin or rod extending substantially in parallel with the optical axis of the taking lens. The cartridge compartment door is designed to be locked at the locking position when the locking member is rotated in the counterclockwise direction. The locking member at such locking condition will be in parallel with the top surface of the camera housing and be close to of or directly contacting with the top of the camera. Should the locking member be rotated approximately 90 degrees in the clockwise direction from that position as viewed from the front of the taking lens, the exposure window of the cartridge will be closed and simultaneously the lock of cartridge compartment door at its closing position will be released.
Also, the moving directions of the cover member inside of the cartridge when the cover member opens and closes the exposure window is predetermined depending upon the types of the disk type film cartridge assembly to be used.
And when the disk type film cartridge assembly is loaded a camera, the exposure window is to be opened by the clockwise rotation, as viewed from the front of the taking lens, of the cover member. Consequently, it is necessary that the cover member connecting member which operates both the locking member and the cover member connects either directly through the gear portions of the locking member and the cover member or via the gears of an even number between them. In conventional cameras two gears are interposed. This is becase if the gear portions of the locking member and the cover member connecting member should be connected directly, at least either one of the members may require a considerably large space during the opening and closing operation, resulting in restriction of the versatility of the design of other mechanisms. In order to prevent such inconvenience, the gears are provided between the two members. In such an arrangement of the conventional camera the operating power is conveyed via two gears and two gear portions resulting in the lowering of power conveying efficiency and higher costs.
Also, another shortcoming of the above mentioned conventional camera is that there is some difficulties in operating the locking member because a photographer may find it difficult to lift the locking member by looking the tip of the locking member with his or her finger since the locking member will be positioned alongside the top plane of the camera housing and especially the tip of the locking member will fall into the concave portion formed on the top plane of the camera housing when the locking member is brought down.